Yes there is an M6 bolt that goes through the armboard and raiser into threaded holes in the Permalli. I threaded the holes quite deep about 30mm to ensure good thread bite and less likelihood of stripping the thread.
I do not but I’m trying to link up with a local machinist who is familiar with hifi, though last I had heard his shop burnt down in 2022, not sure if he has recovered yet.
I have the proof of concept inverted bearing motor together. I haven't run it yet as I need to modify the platter to fit the new rotor.
Pics
Rotor in the lathe being clocked in to bore the journal sleeve's
The journal is ATM just a bit of 12mm linear shaft, it's not perfectly round and quite rough under magnification. This will be replaced later with either Tungsten Carbide or Toolsteel once I have it running and I'm happy with the result.
The cap on the top is the thrust pad. I didn't recess it because I needed the pivot point at this height and the Al I used for the rotor was a little too short (out of scrap bin).
Pics
Rotor in the lathe being clocked in to bore the journal sleeve's
The journal is ATM just a bit of 12mm linear shaft, it's not perfectly round and quite rough under magnification. This will be replaced later with either Tungsten Carbide or Toolsteel once I have it running and I'm happy with the result.
The cap on the top is the thrust pad. I didn't recess it because I needed the pivot point at this height and the Al I used for the rotor was a little too short (out of scrap bin).
I haven't had my SP10 apart in a couple years, so this might be a dumb question: For the inverted bearing are you operating the motor flipped from its original position or just replacing the spindle with a fixed shaft with bearing on top? Apologies if this is a silly question. I don't have the machining capability to duplicate your effort but am impressed and think it could make a difference.
Alright, before heating and removing the bearing cap, would I be best off securing the motor assembly all the way up until the platter (leave platter off,) then access it from the bottom?
Also, when I go to build a new plinth, assuming 2x20mm panzer, the top board will have a cutout large enough to accommodate the platter, then the bottom board will have a cutout large enough to support the motor assembly with the 4 marked holes?
Also, when I go to build a new plinth, assuming 2x20mm panzer, the top board will have a cutout large enough to accommodate the platter, then the bottom board will have a cutout large enough to support the motor assembly with the 4 marked holes?
@FuzzyNightmares I add a couple of drops down the sleeve then touch the spindle with oil so there is a coat of oil on the spindle. A little too much is better than too little. There is a lip around the top of the bearing sleeve to prevent oil spilling into the motor housing.
While you have it apart I would suggest replacing the ball with SI3N4. The steel ball will have marks on it and increase wear on a new thrust pad. My SP10 has been spinning for a couple of years (20-40hrs a week) with an 8kg platter and there is only a very small wear divot in the new Torlon thrust pad.
While you have it apart I would suggest replacing the ball with SI3N4. The steel ball will have marks on it and increase wear on a new thrust pad. My SP10 has been spinning for a couple of years (20-40hrs a week) with an 8kg platter and there is only a very small wear divot in the new Torlon thrust pad.
The inverted bearing came about because I had an SP10 that came from an outback radio station that had not been maintained and the bearing is so badly scored it wont spin in the sleeve.
What I'm trying to achieve is to reduce platter vertical runout and the chaotic wobble all SP10mk2's exhibit. I had a Goldmund Reference here for a while doing some work on it for a friend and its platter vertical runout was 30microns with no visible wobble on the test indicator. The platter rotated very smoothly. This is what I'm using as the benchmark. If I can get close to the Goldmund I'll be a happy camper.
Fuzzy,
I have recently been through this. Asked a million questions and this is what I did and I will do it exactly the same way on my second Motor.
1. I used Bon's bracket method described in the not to distant past. Basically. it is an L shaped aluminum piece that you bolt the motor to through the flange mount holes and stick the other "L" leg in a vice. Use a torch to heat the bearing cap. You won't even have to over due it. I could not get it done with a heat gun. Use a pair of channel locks or other wrench that will get a reasonable grip on it. I was prepared to use a pipe wrench if necessary but that is way overkill with the right heat. I padded the jaws of my channel locs a bit to protect the end cap but still get a descent bite on it. Mine came off easily with the torch.
2. If it were me, I would replace your end cap and definitely the ball with a Si3N4 described by Warrajon.
3. Clean everything and new oil. Should be good as new.
Note: I made a hardwood dowel to drive the old ball out. It took more than I was expecting.
I was a little nervous the first time not knowing what was going to happen. Set it up right and everything should be good using moderation.
Good luck, keep us posted.
Don
I have recently been through this. Asked a million questions and this is what I did and I will do it exactly the same way on my second Motor.
1. I used Bon's bracket method described in the not to distant past. Basically. it is an L shaped aluminum piece that you bolt the motor to through the flange mount holes and stick the other "L" leg in a vice. Use a torch to heat the bearing cap. You won't even have to over due it. I could not get it done with a heat gun. Use a pair of channel locks or other wrench that will get a reasonable grip on it. I was prepared to use a pipe wrench if necessary but that is way overkill with the right heat. I padded the jaws of my channel locs a bit to protect the end cap but still get a descent bite on it. Mine came off easily with the torch.
2. If it were me, I would replace your end cap and definitely the ball with a Si3N4 described by Warrajon.
3. Clean everything and new oil. Should be good as new.
Note: I made a hardwood dowel to drive the old ball out. It took more than I was expecting.
I was a little nervous the first time not knowing what was going to happen. Set it up right and everything should be good using moderation.
Good luck, keep us posted.
Don